Keith Urban "marvels" at what an "amazing" mother Nicole Kidman is.

The two superstars married in 2006 and together they have daughters Sunday Rose and Faith Margaret. Nicole also has adopted children Isabella and Connor with her ex-husband Tom Cruise.

Keith can't believe how well the Hollywood actress balances parenthood with her career.

"It’s always admirable, the fearlessness she has as an artist. She’s always got cool things happening. They’re always eclectic," Keith gushed to The Today Show about Nicole's film projects.

"The thing I marvel at the most is how she does that and takes care of our family. She’s an amazing wife and mother.
"People ask me, 'How do you do it?' I say, 'It’s Nic!'... She’s got all of us so incredibly taken care of. She’s amazing."

It's not just 46-year-old Nicole who has a busy work schedule. As a country singer, Keith, also 46, has produced chart-topping songs and is often away on tour.

"We’re only gone days at a time, not weeks and weeks… And when I’m touring, Nic and the girls come out and join me… The girls love the tour bus!" he smiled.

Last year, Keith joined The Rolling Stones on stage to support them on their tour opening show in Los Angeles. He cites it as the highlight of his career.

"Singing that close to Mick [Jagger] is ridiculous. It’s like an atomic bomb," he grinned.

"It’s like Formula One; you just jump in and hang on. There’s a ferocious energy on stage."

Keith is currently promoting his latest album, Fuse.